[ewg] broken support for UC in rdma_cm

[Eli Cohen]

I just noticed that Vlad already opened a bugzilla bug (1874) on this.
I quote Sean's response:

RDMA CM supports UD and RC QPs (port spaces UDP/TCP) only.  Support
for UC QPs should come from another port space.

This makes sense to me. Still we need to address the issues I raised
below. Sean, are you going to fix this?

On Mon, Mar 15, 2010 at 01:12:28PM +0200, Eli Cohen wrote:
> We got failing tests in our regression that use UC transport from
> userspace. Looking at cma_connect_ib(), I see that it uses IB_QPT_RC
> in the CM request instead of using whatever the transport type of the
> requesting QP. There is no easy way to retrieve that information too
> since the QP is created in userspace. We do have the QP number. One
> way to address this problem is to have an API that returns a pointer
> to struct ib_qp given the ib device and the QP number. Another way
> would be to pass qp_type through the call to rdma_init_qp_attr().
> Thoughts?